I Think My Dads Sudden Death May Have Been The Result Of Foul Play (san Francisco, Ca)

Hello, this is a heavy story so if its too much, please skip. I (F24) recently lost my dad (M51) about 4 months ago. Up until last month, i and everyone involved was under the impression that he had a random cardiac arrest that lead to him losing brain function. He was in the hospital for about a week before we decided to take him off life support. The issue comes along when we got an updated death certificate telling us that they had found fentanyl in his system. This came as a complete shock to everyone. By this time, no autopsy was done and he had already been cremated. I'm not going to pretend like its an impossibility that he could have taken something, but he was not a drug user at all. Also, we called the hospital for more information and they said that ONLY fentanyl was found, which leads me to believe that it is a possibility foul play was involved. I live in LA ,California but this whole situation occurred while he was in San Francisco for work. When he was picked up by the ambulance, his phone was missing and he was in an extremely unsafe area. None of this was communicated to us at all so we had no reason to believe anything was different about the situation for the last three months. I am trying my best to put the pieces of the puzzle together on my own, but i'm wondering if there is anything else i can do to get more help. For one, he never did the icloud thing of allowing someone to have access to it in case of death. I know i need a court order but i've been calling around and i cant figure out how to start that process. I would appreciate any help in this situation as i am pretty lost on what I can do, what I should do and if anyone can even help. Thank you for listening, sorry if this post is a little messy, its been really hard trying to make sense of everything.